A damper of the above kind is described in the German published patent specification DE-3442738A, in which the rotating shaft is divided into two parts, one of which is formed with a chamber in which the said fins are mounted. Bearing means are also provided. Such an arrangement requires a very large number of components, and is relatively complicated as a result of the division of the shaft into two parts.
In consequence, the arrangement is unable to respond, as conveniently as might be desired, to various requirements which are imposed in practice.